Case referent study of brain tumors The etiology of brain tumors and brain cancer is poorly understood, and recorded incidence rates have increased dramatically over the past several decades. In response to these findings, and to advance understanding of environmental, behavioral and genetic causes of brain tumors, we conducted a case-control study of malignant and benign brain tumors. Excess risks of glioma were found among electricians and farmers, and an elevated risk of meningioma was seen among auto-body painters. Recent genetic analyses have indicated associations between brain tumor risk and polymorphisms in cytokine, apoptosis/cell cycle control, DNA repair and oxidative stress genes. Findings for these pathways are being followed up in larger and more comprehensive studies. UV Dosimetry A pilot study of 125 volunteer radiologic technologists was performed by REB investigators in which daily diaries and polysulfone UV dosimeters were used to develop better questionnaire approaches to ascertain environmental UV exposure for future studies of skin and other cancers in this largely female occupational population. The volunteers were queried 6 months later to test the reproducibility of responses to time outdoors. Agreement between reported time on weekdays was significantly higher than for weekends and the reproducibility of hour-based compared to activity-based questionnaires was poorer in adult women. Improved exposure assessment may enable us to characterize more quantitatively the effects of UV and ionizing radiation on skin and other cancers. PLCO Lung DNA Damage Study It is unclear whether the reported associations between functional assays and increased lung cancer risk represent a true association because the tests were performed on biologic specimens collected after cancer diagnosis, that they may be measuring the consequence, rather than the underlying cause of cancer (termed reverse causation bias). Several REB investigators in are participating in the effort to determine the predictive value of several phenotypic or functional assays in pre-diagnostic samples from lung cancer patients included in the Prostate, Lung, Colon, and Ovary (PLCO) screening trial. Analyses are in progress.